We hypothesized that respiratory abnormality may coincide with some FOG episodes. We aimed to investigate the characteristics of respiratory responses in conjunction with FOG in actual daily living.
While walking without FOG, the breathing pattern was regular. However, our patient presented sudden alteration in the breathing pattern not only during, but also just prior to FOG. Respiratory abnormality was characterized by a short period of apneic pause at a high lung volume. Before relief from FOG, deep expiration was observed. 
It is possible that the change in respiration that accompanied FOG was a response to the antecedent emotional stimuli because it occurred even just before the actual FOG episodes. Although the pathophysiology remains unclear, it appears that limbic overload leads to transiently disordered automatic control of breathing. Deep expiration before the restart of gait may be an attentional control toward breathing to release from breath holding at a high lung volume, leading to the resetting of the limbic load.